This invention relates to a method of constructing a list of recorded data in a postscript type optical disk using an optical recording medium and, more particularly, to a method of constructing and recording a list of recorded data in a non-erasable postscript type optical disk within short periods of time.
In a usual optical disk, on which a train of signals are recorded between its inner and outer peripheries by utilizing a laser beam, a list of recorded data is recorded onto the disk. This list of recorded data is called TOC (table of contents), and it provides information about positions of recorded data in the signal train. The position of intended data can be accessed at high speed with reference to the list noted above at the time of the data accessing.
The position of recorded data may be expressed using addresses of frame numbers or the like for each track as in a video disk player where a disk driven at a constant angular velocity (C.A.V.) to reproduce data with an optical pick-up, or it may be expressed using the overall recording time from a point of starting the recording. In the case of a disk (hereinafter referred to it as CD) with digital audio signals recorded thereon, which is called as compact disk known as an example of the latter and driven at a constant linear velocity (C.L.V.) to reproduce data with an optical pick-up, the overall recording time is used as the record position information, and the time point of start of each musical piece, the number of first musical piece, the number of the last musical piece and the last time point of recording are recorded onto list areas on the disk. In an optical disk capable of recording, the status of record of data presently recorded onto the disk, is usually recorded onto a list area, and this list is used for random accessing to data.
When it is intended to record a list onto a non-erasable postscript type optical disk with the same format as for the CD noted above, there is an inconvenience in case the length of recorded data, number of data pieces, etc. are not known until the end of recording of the last data. In this case, the list can not be recorded onto the disk unless all the data have been recorded. In practice, however, it is necessary to access data already recorded onto the disk at high speed even before the end of recording of all the data. Where no list is recorded onto the disk, the same information as the list can be obtained through continuous reading of the data recorded onto the disk. However, the real-time reading of the recorded data from the point of start till the point of end of the recording requires long time.
In the postscript type optical disk, particularly the non-erasable disk, it is impossible to record a list onto the list area of the disk unless all the data have been recorded. Therefore, it has been impossible to access the recorded data at high speed until the end of recording of all the data.
The present invention has been intended in order to solve the above problems in the prior art, and its object is to provide a method of constructing and recording a list of recorded data in a postscript type optical disk, particularly of non-erasable type, with which it is possible to construct list information of recorded data under control within short periods of time even though no list of recorded data is recorded so that recorded data may be accessed at high speed.
The method of constructing a list according to the present invention features the steps of detecting a point of ending the recording of recorded data recorded onto a disk, reading time code data at said point of ending the recording, obtaining a point of starting the recording through substraction of the recording time of the last recorded data from the overall recording time according to said time code data, and storing the obtained point of starting the recording in a time table of the pertinent data number, thereby obtaining a list of recorded data.
The method of recording a list according to the present invention features the steps of detecting a point of ending the recording of recorded data recorded onto a disk, reading time code data at said point of ending the recording, obtaining a point of starting the recording through subtraction of the recording time of the last recording data from the overall recording time according to said time code data, storing the obtained point of starting the recording in a time table of the pertinent data number, initializing a pointer representing a data number to be retrieved next with the data number of said last recording data, reading out the point of starting the recording of recorded data of the data number represented by the pointer from said time table, storing a point for seeking a value with a predetermined off-set from the read-out point of starting the recording in a register, seeking the point of the value in said register by advancing said pointer, effecting compensation for the seek point when the data number after the seeking fails to coincide with the pointer while obtaining the point of starting the recording of the pertinent data and storing it in said time table when the data number coincides with the pointer, and repeating the seeking operation to obtain the point of starting the recording of each data, thereby constructing a list of recorded data and recording it onto a list area of the postscript type optical disk.
According to the present invention, the point of recording of the last data is detected, and the point of starting the recording of the last recorded data is obtained from the pertinent time code data. On the basis of the data of the recording start point the preceding data area is sought to find the point of starting the recording of that data. This process is repeatedly done progressively. In this way, a list of all recorded data recorded onto the disk is constructed at high speed under control of a system controller. The list thus constructed is recorded onto a list area of the postscript type optical disk.